270 CDI Starting issues

[Wearethesound]

It was a Mann I believe. I was told that was a pretty good brand. I used epoxy and sealed up the filter bowl where I suspect the leak and will try again today if there is still air present I'm going to order both of those lines and there is still air I'm going to replace the filter and filter bowl. I need this thing drivable ASAP. can't lose much more time or money I've already spent half what I paid for it in repairs.

 

[Wearethesound]

Filter bowl housing is the problem, seems to be a leak that is only present under higher revs. New one ordered should be here today or tomorrow. Hopefully that will be the end of it. I only find it after I removed the housing and cleaned everything with degreaser before I applied the sealant and after I filled and primed the housing I Noticed a wet area while running it up.

 

[MOZ]

Fingers crossed for you, I feel your pain. Nothing more frustrating than chasing a problem for a long while

good luck
Moz

 

[Wearethesound]

Well new filter housing, along with a new Mercedes filter and all new o-rings and the issue is way better. But not completely solved. Now I'm noticing when I shut off the engine a nice big bubble is forming on the hose in-between the filter and "heat exchanger?" I was thinking about this problem (I know tmr hinking is a scary thought) and since this system is a suction lift style system, and it operates on a closed loop vacuum to keep positive fuel flow at all times then there would need to be a vacuum relief valve somewhere to allow free air flow into the tank to prevent system cavitation. My thought is this, what if the relief valve is barely opening or not opening under low suction (ie starting/shutdown) allowing a hard vacuum forcing "cavitation" or negative over pressurization of my fuel system causing a leak from the weakest point.... The plastic fuel filter housing??? Has anyone heard of issues with a relief valve or maybe it's a "flapper" style valve? Idk might be too dumb to comprehend this system with out schematics, or I'm over thinking it.

Oh a good note she made the family trip to and from chessington yesterday without any issues. I'm happy with improvements but I still want this issue solved!

 

[MOZ]

Sounds like progress, not sure if yours being a 2000 has a slightly different layout and components to my 2003 facelift model (I do know the fuel pipes have 2 different versions and the low pressure entry to the High pressure pump has 2 variants.

I'm not clear as to what you mean by your filter housing as mine is just a sealed metal fuel filter (with an inlet rubber hose from the fuel heater (is this the hose where you see the bubble? - mine is solid black rubber so wouldn't see a bubble forming there on mine, and a female output for the plug in hard plastic fuel pipe which goes straight to my low pressure pump at the front of the engine (no heat exchanger between the filter and the LP pump on mine), and the filter just sits in a strap retainer cup to hold it in place (doesn't act as any seal, just holds the filter from vibrating).

Dont suppose you have any photos of your engine bay do you, just for curiosity as Ive not seen under a non facelift before.

Not sure if there is a valve or not, maybe someone else can confirm?

I know on mine there is a 3 ended fuel pipe (with a t piece branch) between the LP pump output to the HP pump inlet, then the T branch off to a valve type thing which bolts to the top of the engine but does nothing (I believe this is to allow a mechanic to insert a pressure tester to check fuel pressure - I may be wrong) and I have always wondered if air could get in there if that failed, but as i said before not all 270's have this extra T piece so not sure if yours does or doesn't (not that I'm saying that's your problem) but again curious if yours is slightly different to mine.

Sounds like progress
All the best.
Moz

 

[Wearethesound]

I have a picture but I don't know how to get it from my phone to here. I've seen the type your talking about and even thought about converting mine to be like your set up but I think I have a different fuel heater set up since mine has a the hard plastic hose coming out of the heater to the filter housing and the same type hose going from the housing to the LP pump. I replaced both those plastic lines, the filter insert and the housing.

 

[MOZ]

Fingers crossed that fixes it once and for all.

If your using a computer to post on here you can use the paper clip attach icon on the editing toolbar while writing your post to attach a picture, when you press it another window opens asking you what picture you want and then uploads it.

There is an mbclub app that I use on my phone and that lets you insert a picture, using one of the menus.

All the best, let us know how you get on.
Moz

 

[Wearethesound]

Sweet this app will be handy! Here's the picture of my engine bay.

 

[Wearethesound]

I'm wondering if changing my setup to what you have (steel canister style) will fix my issue? Or if I'm having a over vacuum pressurization problem due to a faulty vent/relief valve would cause a cavitation issue once I remove the weakest components from the system? I noticed it most commonly happens on short drives or 20-25 minute back road drives where I'm not maintaining a steady speed. Air seems to build up in the filter then it won't start unless I wait an hour or two or unless I fill the filter bowl back up with diesel. The 2 hour drive to south London and then back I didn't have one issue and when she starts she fired up first turn of the motor, way quicker then she was before I started digging into this mysterious mess of a leak.....

 

[MOZ]

Yep slightly different to mine ( see attached- taken after fitting new fuel line at front ( with pressure test valve branch on the top of the engine) just before replacing my fuel filter and the hose from the tilted to the long pump.

Don't know whether it's a common conversion but maybe worth looking into if you can swap out your filter set up for a simple canister one, it looks like the same fitting for the line ftom the filter to the long pump, but the inlet side is different, mines just a black rubber hose with a jubilee clip whereas yours obviously uses another rigid pipe and clip fittings.
My black hose goes back about 6 inches to a 2 hose terminating rectangular per heater - again just pushed on and jubilee Clip.

Worth searching for a conversion diy to see if anyone else has done it if your still having problems with it.

Good luck and thanks for the photo.

Moz

 

[Wearethesound]

Welp she's dead now about an hour from home and 2 hours from our destination.

 

[MOZ]

Doh!!! gutted for you.

Bet your'e well fed up with it now, I know I got fed up with mine when I had fuel delivery issues, and I didn't have anywhere near as much hassle as you are.

Good luck.

Moz

 

[Wearethesound]

So they are telling me it's a crank or camshaft sensor or its a timing chain since it is dying once it's warm. Something to do with messing with the timing sequence or something. Idk. I don't see how this explains the fuel filter housing being full of air and not diesel after it dies? Nor does it explain the air in the fuel lines?? Anyone??? Or should I just call someone else?

 

[camerafodder]

Have you replaced the seals at the low pressure side of the high pressure fuel pump on the front of the engine?

 

[Wearethesound]

I have not as the only bubbles I noticed when it's running are coming from the "out" line of the fuel filter but none inside the "in" line.

 

[Wearethesound]

Well finally got it sorted out. Apparently I had already fixed the fuel issue and my cam shaft sensor went out causing it to die/ not start intermittently as it was with the fuel issue which had led me to believe I hadn't solved it. Part changed and boom she's as good as new...... So far.